Air Brake Coach
System failuresQuestion 46 of 116

You have a park and emergency circuit failure. At about what pressure do the spring park brakes begin to apply?

  1. 100 to 110 PSI
  2. 20 to 25 PSI
  3. 55 to 60 PSI
  4. 120 to 135 PSI
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Correct answer: 55 to 60 PSI

Apply the service brake steadily. The spring park brakes begin to apply gradually near 55 to 60 PSI (380 to 414 kPa).

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 7: System failures, page 71

Practice system failures

Questions last reviewed: 18 October 2026